Hydraulic press cycle control system



May 26, 1953 L. A. CAMEROTA HYDRAULIC PRESS CYCLE CONTROL SYSTEM 6 Sheet'SSheet 1 Filed Dec. 15 1951 d 1 w m R w m a m p m a J P 1% mm m M h NN L 1 Q .%Q\ 5 L w 53:28 QR T N T kw L m O \fiqmwwwkq \N o wfiwwwoxm QSSR 1N IUQEI ATTORNEYS.

L. A. CAMEROTA HYDRAULIC PRESS CYCLE CONTROL SYSTEM May 26, 1953 6 Sheets-Sheet 2 Filed Dec. 15 1951 QQQKEQQ WQ N QNRN INVENTOR: [ax/1814121720024, [1 a? 21 ATTORNEYS.

May 26, 1953 L. A. CAMEROTA HYDRAULIC PRESS CYCLE CONTROL SYSTEM 6 Sheets-Sheet Filed Dec. 15, 1951 MJ QN 1 J g INVENTOR: Z 01/1191 1 Fame/ 02 41 fimw ATTORNEYS.

May 26, 1953 1.. A. CAMEROTA HYDRAULIC PRESS CYCLE CONTROL SYSTEM 6 Sheets-Sheet Filed Dec. 15 1951 w J QNRM INVENTOR:

A. (a/22 Mia, 524

ATTORNEYS.

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May 26, 1953 L. A. CAMEROTA 2,639,585

HYDRAULIC PRESS CYCLE CONTROL SYSTEM Filed Dec. 15. 1951 s Sheets-Sheet 5 FJGL i INVENTOR; Zaaaulfamemfia,

ATTORNEYS.

May 26, 1953 A. CAMEROTA HYDRAULIC PRESS CYCLE CONTROL SYSTEM 6 Sheets-Sheet 6 Filed Dec. 15, 1951 0 b w nllllll f y-l NE H N QMMN QWN rl. I I

V mm la /13H BY (51 ATTORNEYS.

Patented May 26, 1953 HYDRAULIC PRESS CYCLE CONTROL SYSTEM Louis A. Camerota, Burlington, N. J., assignor to The Florence Pipe Foundry and Machine Company, Florence, N. J., a corporation of New Jersey Application December 15, 1951, Serial N 0. 261,842

This invention relates to hydraulic press operating systems, that is to say, to systems for operating hydraulic presses under cycliccontrol. The chief aims of my invention are to enable 9 Claims. (Cl. (ill-=52) master valve 28; and the pressure of the oil delivered by said pump is governed, in turn, by an auxiliary or remote control valve 29 arranged to be controlled by a compressed air diaphragm the use of a constant speed variable output r- 5 motor 30, under governance of a cycle timing tary pump in an operating system for a hydraulic and pressure control instrument 32 on a control press, and to provide automatic means which panel 33. During opening of the press, oil drains can be relied upon to accurately control the from the ram cylinders 23 by way of piping 35, pump, after closing of the press, in such manner 33, 31 and 38 back into reservoir 25, the delivery that the material worked upon is subjected to a from pump 26 being also returned to said reserdefinite predetermined pressure or pressures durvoir at the same time by way of piping 39, 40, ing a cycle period of prescribed duration. 4| as shown by the arrows in Fig; l. During Other objects and attendant advantages will closing of the press, the oil delivered under presappear from the following detailed description sure by pump 26 is conducted to the ram cylinof the attached drawings, wherein: l5 ders 23 through piping 3Q, 43, 33 and 35, like- Fig. 1 is a more or less diagrammatic view of wise by way of master valve 28, as indicated by a hydraulic press with a cycle control means the arrows in Fig. 2. Part of the pumped oil is conveniently embodying my invention, the press conducted through a branch pipe 42 to auxiliary being open and the pump idling. or remote control valve 29 and from thence re- Fig. 2 is a view like Fig. 1, with the press closed 2 turns to the pump by Way of pipe 43. The purand the pump maintaining prescribed pressure pose of the other pipe connections designated 44, upon the material undergoing compression. 45, 46 and M will be explained later herein. Com- Fig. 3 is a view drawn to a larger scale showpressed air is used. in the control, the same being the pump and certain of the control elements ing delivered from a suitable source of supply in section, withthe press open and the pump (not shown) to the time pressure cycle control idling as mentioned above in connection with instrument 32 on panel 33 through a pipe line 50, Fig. 1. g the delivery pressure being regulatable by a pres- Fig. 4 is a view like Fig. 3 with the press closed sure reducin valve 5| interposed in said line. and with certain of the control elements func- There is also an air flow connection 53 between tioning under the conditions mentioned above instrument 32 and the diaphragm motor 33. in connection with Fig. 2. Although the pump 23, the master valve 28, Fig. 5 is a view in longitudinal sectionof a the auxiliary valve 29, the diaphragm motor 30 master valve included in the control ,means, and the time-pressure cycle control instrument 32 showing the direction of fluid flow therethrough are generally speaking, of known construction, during idling of the pump and opening-of the 35 they will be briefly described so that their conpy gj certed action in controlling press operation in Fig. 6 is a view like Fig. 5 showing the direction accordance With y invention, W e m e readof fluid flow through the master valve during Y understood closing of the press; and The pump F g. 7 1s a diagrammatic view of a cycle gov- 40 As exemplified in Figs 3 and 4, pump 26 is of a ernlng instrument incorporated in the control, type having a fixed axis 56 which is housed and the connections between Said instrument and within'a slide block 57 which serves as the stator, Certain other elements of the control and which is constrained to horizontal move- In 1, the Press to be controlled ment within the pump casing 58. The output of prehensivelv designated 26; the S heme, by pump 26 is varied by shifting of slide block .51 Way of example. of the multirleien type With a relative to rotor 53, the shifting being accomfiXed p head 2|, with a movable bottom plished in one direction upon admission of 011 head 22 arranged to be actuated by a pail of under pressure into a bore 53 in one side of cashydraulic ram cylinders 23. The hydraulic fluid, ing 5.8 behind a piston til abutting said slide which may be oil, used to Operate h press is block. Upon relief of pressure in bore 53, a drawn from a reservoir 25 by a variable delivery spring 6| within a hollow 62 at the opposite side rotary pump 26 which is driven at constant speed of casing 5B acts to shift slide block 51. in the by an electric motor 27. Introduction and exother direction. The maximum output of the haust of the oil into and from. the press cylinders pump can be changed by regulating the volume 23 'is via --a. magnetically-actuated. four ,,way adjusting screw indicated at 63 which limits the 3 extent to which slide block 51 can be moved to the left by the action of spring Screw 63 is threadedly engaged in an offset 04 on pump casing 58, and disposed between it and piston 60 in axial alignment, is a plunger 66 with a piston head 61 at one end thereof, said plunger being maintained in engagement with mid piston by a spring 68. The oil for actuating piston Ellis delivered to a port 65 in oiiset S4 and through pipe 43 into the central chamber 69 of said offset and reaches the bore 553 by way of a connecting passage 10. As block 51 is moved to the right, plunger 60 urged by spring 68, follows with the result that, through attendant displacement of the piston head 61 on said plunger, the oil is permitted to flow from the central chamber 539 of offset 6 1 into storage tank 25 via the passage indicated at I I. As further shown in Figs. 3 and 4, the pipe 39 connects with the pressure port t2 of pump 26, and the suction port E3 of the latter is in communication. with the storage reservoir by way of a passage I4.

The master valve 30. of valve 28 is maintained in. the position in which it. is shown inFigby a spring 3%,. so that oil flowwill take place in the direction of the arrows, i. e.. from pipe 36 via ports. I8- and I5 into exhaust pipe. 31. The flow from pipe 40 passes through. ports. I S and I9 into: pipe II and exhaust pipe 38. to reservoir 25. Upon shifting. of piston 30 in. opposition to spring. 3| tothe position of Fig, 6.. when the press 20. isto be closed (-Fig. :2), flow of. the oil will take. place from pipe 40 via ports I5 and. I81 and pipe 3 6. The actuatin meansior. master valve 201s in. the form of an associated. pilot valve. 84 whereot the plunger 85-is connected to thearmature 86 of anoperatingsolehold 81 interposed in. a circuit 88-. As shown,

pilot. valve 84 has spaced portsv 89 and 90. into which, the. pipes. 41 and 46 respectively connect.

(not shown) associated: with the. pump, or from an entirely separate source of; pressure: fluid. Normally, plunger 85 of. pilot valve. 84= is held. in the raisedapositionof. Fig. 5.-bya spring!) I. to perexhausting of oil fromthe space 02 forward oi the head 80a of, piston. 80 of valve 28: via. the port sit-93 to port90 and pipe 40. Upon energizationofsolenoid 8.1 anddepression of. the. plunger 35 of pilot valve 84, pressure fluid. from pipe. 04 passes through port 89. to the port at 94 and into the space 92 to shift piston 80 of valve 28 rightward rto the' position in which it is shownin Fig. 8-. Normally-port 04 is closed, as shown in Fig. 5, by a spring-backed stop 85 which yield to pressureand thus permits flow of oilinto'space 92 in the: manner just explained. Flow through port 03. isaregulatable by a screw 90 whereby: the leftwardimovementof'piston 80 of master valve "is controlled.

The auxiliary or remote. control. valve:

Except: ashereinafter pointed out, auxiliary or remote control. valve. 29 is of well. known construction in. that. it. has an upwardlyprotruding st'em: I 0.0: which is: axially slidable in theupper-or neck: end of the. valve body: 101 The lower end oi 'the stem Illll bearsuponacup piston Win the upper portion of the main bore I03 of the valve body. Within the lower portion of the main bore I03 is a cup piston I 05 with a diametricallyreduced pendant axial prolongation I06 which extends down into the correspondingly reduced bottom end I01 of the bore I08 to control oil flow through a lateral passage I00 between the ports I09 and H0 of valve 29. The cup pistons I02 and I05 are normally maintained in the positions in which they are shown in Fig. 3, by a helical compression spring III. The lower end of spring III bears against a collar H2 at the corresponding end of a thrust pin H3 which, in turn, bears upon cup piston I05. Pin H3 is slidable independently of valve stem I00 with its top end passing through an axial aperture in cup piston I02 and capable of entry into an axial socket bore in the bottom end of said stem. At its top end, spring III bears directly upon cup piston I02. Upon moving upward, cup piston I05 shutsofi communication between the port I I5 and the main portion I03 of. the valve bore and. at the same time establishes communication between the ports I01 and. III. A vertical passage IIB connects the ports I I 0 and H1 within the valve body, and in accordance with my invention, the port H0 is in constant commumi'zation, through a. bypass pipe IIt, witha port III! which extends into aho11owI20 directly above cup" piston I02 within the valve body.v As a consequence of the latter provision, the oil pressure on opposite sides of cup piston I02 is equalized. As shown, port I09 of valve 20 1s connected to the pressure port I2 of pump 26 by the pipes 42 and 39, and port H0 is connected to port 65 in the offset of the pump casing 53 by pipe 43. Associated with valve 2.9 and. supported by a bracket I25 rigidly afiixed to the upper or neck portion of said valve, is the actuating diaphragm motor 30'. To the diaphragm I25 of motor 30 is amxed a disk I21 which, in tum, is-secured to an extension I28 of stem I00 of remote control valve 20.- Downward movement 01'. valve stem extension I38 is yieldingl y' resisted by av helical compression spring II! which. is. housed. in a thimb'l'e: cover I30 secured to the. casing of motor 30.

The time-pressure cycle control instrument In the time-pressure cycle control instrument 3!, see Fig. '7; the rotary pronle cam designated I30 is slowly rotated by an electric motor I3I interposed inan electric circuit I32; and against the periphery of said cam rides the distal or point end of a follower arm I'33'whichi's arranged to swing in suspension about a fixed axis T30. Medially fulcrumed within the yoked portion I331: ofcam follower'ann I33" is ahorizontal lever I33 whereof one extremity is coupled, by means of a link I36, with the arm I37 of a hydraulic pressure-responsive coil I38 which, through pipe 41 is connected to'pipe 35 that leads to the ram cylinders 23. Theother extremity or'lcver: I33 is coupled, by means of a drop link I40, to one extremity 01'- a bell crank I4I fulcrumed within anotheryoke -portion I33b of cam follower arm" I33. By meansiofa horizontal link I42, the other extremity'of' bellcrank MI is coupled with the top end of av vertically-arranged proportloning lever I43. At its lower end, proporti'oning lever'" M3 is pivotallyconnected tothe distal end or a horizontally-arranged arm I45 which is fiilcrumed on afixedsupport I46 Asshown, arm" I'l5=l1es'be'- tween the: reset and proportioningbellows I41 and H0 whereoftheformer is'in communication, byway or a; tube HO. with a capacity tank I00.

.aosarssrs Extending between tube I49 and a tube I5I leading into the bottom of the proportioning bellows I48 is a shunt tube I52 wherein is interposed a capillary resistance coil I53. Further included in control instrument 32 is a relay I55 whereof the casing is subdivided, by a partition I56, into two chambers I57 and I58 which latter are in communication at the top by a narrow passage I53. Connecting into chamber I58 of relay I55, at the top, is pipe 5|] through which compressed air is conducted from the supply source. A diaphragm I60 within the chamber I58 of relay I55 is relied upon to move a valve closure I6I toward and away from a transverse port I62 in partition I56, such movement being yieldingly resisted by a finger spring I63. The space I65 within the diaphragm is in communication with the exterior through a bleed port I66. Another tube I61 leads from chamber I58 of relay I55 to a nozzle I68, bleeding of air through the latter being regulated by a flapper H59 pivoted at I'Ifl. An arm III also pivoted at IIB in fixed relation to flapper I69, rests upon a stud II2 projecting laterally from proportioning lever I43.

Operation Assuming the press to be open as in Fig. l, the plunger 83 of master valve 28 to be positioned as in Fig. 5, and pump 25 to be driven by motor 2? and idling, the press attendant, through suitable switch means (not illustrated), causes the circuits 33 and I32 to be closed. By consequent energization of solenoid 87., piston 35 of pilot valve 86 is depressed as in Fig. 6, permitting actuating pressure fluid delivered by way of pipe 35. to enter cylinder 92 as a result plunger 80 of said master valve is shifted rightward against the resistance of spring SI as in Fig. (-3 to establish communication between ports I3 and T8. The pressurized oil then flows from pump 26 through pipes 39, 33, through ports It and E8 of master valve 23, and through pipes 35, 35 to ram cylinders 23 to lift the movable press head 22 until the material M to be compressed is contacted as in Fig. 2. As the pressure builds up in ram cylinders 23, it also rises at port Ill'l of auxiliary remote control valve 23. When the pressure at port I07 of valve 29 attains a value such that the upward force (hydraulic pressure times the area of valve piston Iliii) just balances the downward force (air pressure from the pressure control instrument 32 times the area of diaphragm I26 in motor 33), the hydraulic pressure from the system is applied via ports I87 and III] of valve 29 and passage 'IIl in oiTset 63 of pump housing 58, whereby the piston t and slide block of pump 23 are shifted rightward to reduce the delivery of said pump to a point just sufiicient to provide enough oil to compensate for any leakage in the system. As the slide-block 51 moves toward center position, the plunger 63 follows until the passage II is uncovered eventually to allow excess oil to bleed back into storage tank 25. Due to closing of circuit I32 at the initiation of the cycle, cam I393 of time-pressure control instrument 32 is started in clock-wise rotation as indicated by the arrow thereon in Fig. 7, whereby follower arm I33 is gradually moved rightward by the rise of the lobe I3lla of said cam. If at this time, the arm I3? of pressure responsive coil I38 remains stationary, proportioning lever M3 will likewise be displaced to the right by motion imparted thereto, through parts I36, I35, MI, and I42. Flapper I39 will thereby be positioned to more nearly cover nozzle I68 and thus restrict air leakage, by way of tube I61, from chamber I58 of relay I55, with consequent increase of the pressure on the corresponding side of diaphragm I36 and wider opening of valve IEI to allow more air to pass through tube 53 to the diaphragm motor 33 of auxiliary control valve 29.

When the press is closed and the hydraulic pressure in the system begins to rise, arm I37 of the pressure-responsive coil I38 in instrument 32 is moved counter-clockwise whereby, through the interposed linkage, proportioning lever I43 is displaced, this time to the left. As a result, flapper I69 is moved away from nozzle I63, with attendant decrease of pneumatic pressure on relay I55 and movement of valve I 6| toward closed position. Under these conditions, excess air from the diaphragm motor 33 of remote control valve 29 will bleed through orifice I35 to the atmosphere. Assuming that instrument 32 has been on successful control and that conditions are so balanced that a pressure exists in the proportioning and reset bellows I41 and M8, the same pressure will exist in pipe 53 to the motor 33 of remote control valve 29. If a disturbance occurs, for example, when the depression I3Bb of rotary cam I30 passes the contacting end of follower arm I33, proportioning lever I43 will be moved to the left about its pivotal connection with arm I45, thereby causing flapper I39 to be retracted from nozzle I63 with attendant decrease in the pneumatic pressure upon the right side of relay diaphragm I60. Valve I6I of relay I55 is thereby moved toward closed position and so allows exhaust of air from proportioning bellows hi8 through orifice I65 as a result of which arm I45 is forced downward by bellows I4'I to lower proportioning lever I43. Flapper I69 is thereby moved to more nearly cover nozzle I38 once more. Then, due to decrease in the output pressure, air is allowed to bleed through the resistance coil I53 from the reset bellows I41, whereupon proportioning lever I l3 will be lifted to retract flapper I59 from nozzle I68. The pressure in control relay chamber I53 will thus be decreased and valve I6I will therefore pass less air to tube 53 leading to diaphragm motor 30 until the decreased pressure in proportioning bellows Ml causes it to lower proportioning lever I43 and thereby allows flapper I69 to approach closer to nozzle I63 once more. This re-setting effect will continue until the pressure on the diaphragm of motor 30 has decreased sufiiciently to produce the required air pressure which will permit the hydraulic pressure in the system to decrease to a value determined by the position of follower arm I33 on rotary cam I30. When, and only when this condition obtains will the pressures in the proportioning and re-set bellows l4! and I 18 become equal and equilibrium be restored. All of the above controlled actions actually take place simultaneously. As the pneumatic pressure on the diaphragm motor 30 is increased, the stem Hill of remote control valve 29 will be depressed to increase the force of spring III and prevent rise of piston I05; while as the pressure on said motor is relieved, said piston will be raised by the hydraulic pressure in the system to shut ofi oil flow at H5 and clear passage Iilfl to permit flow of oil from pump 26 to bore 59 in the pump casing 58 as indicated by the arrows in Fig. 4. Slide block 5? is accordingly shifted rightward toward center to decrease the output of pump 25. Due to the shunt pipe lit, the pressure on opposite sides of the piston I02 of valve 29 is equalized as has already-been pointedout: hereinbefore. Piston J02 willtherefore respond easily and quickly to the dictates of diaphragm motor 30.. As shown, cam 130 of .controlinstrument 32'(Fig. '7) may be provided with additional lobes 13% and i300 with intervening valleys, to determine imposition of further pressure upon the. material M at spaced. intervals, and the control cycle may, involve either a single revolution or press 28 to open by action of gravity upon the,-

movablehead E2 and .on ,theram pistons.v

From the -foregoing itwill beseen that,.,after the press closes upon the work, the. timepressure control instrumentftii .takes,over to determine. through thelmotor 30 .and. .valve -29, thev pressure or.,pressures to which thematerialisto be sub- .jected within the definite timerange of .the. cycle.

Having thus ,described. my invention, .1 claim: 1. In combination, a. hydraulic press having relatively movable heads-and an actuating ram.

cylinder; .a constant speed rotarypumphavinge stator and 1a relatively .shiftable rotor, yieldin means tending to .shift therotor into eccentric relation to. thestator, ,and hydraulic ,pressuren-e sponsive meansior shifting the rotor. in OlQPosi-- tion.to the. yieldingmeansto vary. the output of the pumpypiping. betweenthe ranrcylin'der of the press and.v the pump;.an interposedmaster valve allowing upon actuation, delivery ofpressure fluid'by the.pump to the ram cylinder ofthe;

pressto closethe latter; and ,an automatic cycle control. means operative, upon closing of the press, to. thereafter. governthe action of'hydraulic pressure-responsive .rotor-shifting ineans of the pump and so. regulate the latter, for. imposition of prescribed variable pressuresrepeatedly upon the material under compressionfor a definite time interval, said control means, including an auxiliary valve interposed in a branch conduit'between the pipingand the hydraulic pressure-responsive To the press andthe pump; an interposed master.

valve allowing .upon actuation, delivery, of pressure fiuid by the pump tothe ram cylinder of the press toclose the latter; and an automatic cycle control means operative, upon closing of the press,.to thereafter govern the action. of; hydraulic pressure-responsive rotor-shifting means of the pump andso regulatethezlatter for imposition of prescribed variable pressuresrrepeatedly upon the material under compression fora definite time interval saidcontrol means including anaux iliary valve interposed in a branch conduit between the piping and the hydraulic pressure-repon iv rhi n ea s of he. mp,-.Pr surefiuicl-responsivemotor means .tendingtdhold the auxiliary valve. closed against .thehtidraulic pressure, a rotaryprofile cam and ;a ;follow,er;.arm associated therewith, and means actuated through the follower .armto vary the .flow. of pressure fluid to the motor means andthereby allow said auxiliary valve to openwhen the prescribed pressure upon the material isiattained,

3. In combination, a hydraulic, rpltesssghaying relatively movable heads and an ac u tin -m cylinder; .a constant speed rotary pump having a stator and a relatively. shiftable,rotoi;, yielding means tending to shiftthe rotor into eccentric relation to the. stator, I and hydraulicpressureresponsive meansior shifting-the,rotor in opposition to the yielding nieansto vary theoutputiof the pump; piping between theram cylinder of the pressandgthe,puinp; an interposed master valve allowing, upon, actuation, .deli.very; of. pressure fluid bythe pump ,totheram cylinder ofthe;p;re$S to close the latter; and an automatic-pyple cfintrol means operative, upon closing of the press. to thereafter govern the action of hydraulic pressure-responsive rotor-shit ting means of 31111.6. pu p and so-regulate the latter for imposition,otprescribed variable pressures repeatedly, upon the material under compressiouforadefinite time interval, said control. means inoluding a no1 mally closed auxiliary valveinterposed; in a; .b,ranch conduit between the piping .and;-the hydraulic pressure-responsive rotor-shifting means of the pump; a pneumatic ,diaphraginmotor tending to hold the auxiliary valve closed aga nst the hydraulic pressure, a rotary profilecam anda follower arm associated therewith, and means actuated through the follower arm to vary the flow of compressed air to the motor-and tliiereby allow said auxiliary valveto open when the prescribedpressure upon the material is attained 4. The invention according to clairnl, wherein the master valve is of the piston type, andprovided with yielding meansoperative to keep the piston normally positioned-for flow of fluid in the system in-a directiontolgeep .the press open; and wherein an associated magneticallyractuated pilot valve controlsaccess of pressurefluid to the piston of the master valve to shift the latter in opposition to the yielding meanssothat fluid flow in the system-will be inthe direction to close the press.

5. The inventionaccording to claim 2, wherein the automatic valve has a main bore, a. closure element slidable in the-bore, acompression sprin urging the closure toward closedpositioma piston-like backing element for the springalso within the bore adapted to be acted upon'by the motor means, and a by-pass for equalizationof.pressure upon opposite sides of said piston-like element- 6. In combination, a, hydraulic press having relatively. movable heads and an actuatingram cylinder; a constant speed. rotary pump having a pressureport, a suction ,port,,a,stato,r and a relatively shiftable rotor, yielding means tending, to urge the rotor into eccentric. relation to the,stator, and hydraulic pressure responsivemeans opposing the yielding means for shifting the rotor tovary the output of the pump; a storagetank for operating fluid in communication. with the suction port of thepump; a master valveallowme. upon actuation, delivery of pressure fluid from the pump to the ram cylinder; of the press;

the pump to the master valve; flow and return pipe lines respectively extending from the master valve to the ram cylinder and to the storage tank; a branch pipe extending from the first mentioned pipe line to the hydraulic pressureresponsive rotor-shifting means of the pump; an auxiliary valve interposed in the branch pipe having a piston subject to fluid pressure in the system for controlling fluid flow through the branch pipe; a motor tending to keep the piston of the control valve in closed position against the hydraulic pressure; and means operative, upon actuation of the master valve and closing of the press, to govern the motor means and thereby allow the auxiliary valve to open when the prescribed pressure upon the material is attained.

7. The invention according to claim 6, wherein the motor means is operable by compressed air; and wherein the governing means varies the flow of compressed air to said motor during the cycle.

8. The invention according to claim 6, wherein the motor means is operable by compressed air; and wherein the governing means includes a valved relay interposed in a compressed air pipe line extending to the motor and having a bleed outlet; a rotary profile cam with an associated follower arm, and means actuated through linkage connections with said arm for controlling bleed discharge from the relay.

10 9. The invention according to claim 6, wherein the motor means is operable by compressed air; and wherein the governing means includes a valved relay interposed in a compressed air pipe line extending to the motor and having a bleed outlet; a rotary profile cam with an associated follower arm, and means actuated through linkage connections with said arm for controlling bleed discharge from the relay; and means responsive to fluid pressure in the system and influential upon the linkage incident to fluid pressure changes to modify the relief of the relay through the bleed outlet.

LOUIS A. CANIEROTA.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,240,898 Wiedmann May 6, 1941 2,250,539 Landenberger July 29, 1941 2,298,358 Ernst Oct. 13, 1942 2,417,858 Becker Mar. 25, 1947 2,424,300 Becker July 22, 1947 2,436,986 Ashbaugh Mar. 2, 1948 

